Rotary percussion drill having a hydraulically actuated percussion device



United States Patent Inventor Albert Phillips 465 Kiwanis Ave., Morgantown, W. Va. 26585 Appl. No. 807,388

Filed March 14, 1969 Patented Dec. 15, 1970 ROTARY PERCUSSION DRILL HAVING A l-IYDRAULICALLY ACTUATED PERCUSSION DEVICE 8 Claims, 13 Drawing Figs.

US. Cl. 173/105,

173/134, 173/57, 91/39 Int, Cl E2lc 1/12 Field of Search 173/ 134- [56] References Cited UNITED STATES PATENTS 3,005,442 10/1961 McMillan 9 l/40X 3,213,615 10/1965 Bjornberg .r 173/134X Primary Examiner-Ernest R. Purser Attorney-Stanley J. Price, Jr.

ternately to the openings in the cylinder on opposite sides of the piston and to alternately vent the pressurized fluid from the cylinders. Pressure accumulators are employed as surge devices for excess fluid supplied to the cylinder for each stroke of the piston.

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2. Description of the Prior Art In underground mines the roof of the entries or tunnels are supported by expansion-type roof bolts. The bolts are inserted in drilled holes that are arranged in predetermined spaced patterns. The drilling of the boltholes consumes a substantial amount of time and contributes substantially to the overall cost of the mining operation. The boltholes were, in the past, drilled by rotary drills and it was found by using a high rotary speed and imparting percussive forces to the drill rod that it was possible to increase the rate of penetration of the drill rod and thus reduce the time required to drill the boltholes. The percussive forces applied to the drill rod were imparted either by the conventional air-type reciprocating devices well known in the percussive drill art or imparted by-the-action of eccentric weights. The use of air underground, especially in coal mines, is discouraged because the exhaust air adjacent the drill rod increases the dust hazards. There have been several proposals in the past of imparting the percussive forces to the drill rod by a hydraulically actuated device. To the best of my knowledge none of these devices have been commercially successful. There is a need, therefore, for a hydraulically actuated percussive device that may be used with a percussion drill or associated with a high-speed rotary drill to impart percussive forces thereto.

SUMMARY OF THE INVENTION The herein described invention relates to a hydraulically actuated reciprocating piston. Hydraulic fluid under pressure is supplied alternately to the piston cylinder assembly onopposite sides of the piston from a multivalve control device to open and close the valve ports within the valve to supply pressurized fluid alternately to opposite sides of the piston and to alternately vent the cylinder on opposite sides of the piston so that the timing device controlling the opening and closing of the valves thereby control the rate of reciprocation of the piston. The timing device may alsobe employed as a positive displacement pump to supply the fluid to 'the control valves. The piston cylinder assembly may be connected to either a percussive drill or to high-speed rotary drill to impart percussive forces to the rotating drill rod.

The principal object of this invention is to provide a fluidactuated device that includes a multivalve control device which alternately supplies fluid under pressure to opposite sides of a reciprocating piston within a cylinder.

Another object of this invention is to provide a reciprocating device wherein the timing device for supplying pressurized fluid to opposite sides of a reciprocating piston within a cylinder also functions as a positive displacement pump.

Another object of this invention is to provide a reciprocating device in which the cylinders on opposite sides of the piston are connected to pressure ports and vent ports of a multivalve control device and accumulator devices are provided to displace the excess .fluid supplied to the cylinder.

Another object of this invention is to provide a reciprocating piston in which the cylinder is provided with a liquid shock-absorbing means for the piston at opposite ends of its stroke. 7

Another object of this invention is to provide a percussion drill with a hydraulically actuated percussion device.

Another object of this invention is to provide a reciprocating device wherein the volume of liquid displaced by a timing and metering device will correspond with the volume of liquid required to displace the piston in the cylinder for a complete stroke of the piston.

These and other objects and advantages of this invention will be more completely disclosed and described in the following specification, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a view in elevation of the multivalve control device illustrating the plurality of inlet and outletports for the pressure and vent valves and the timing device.

FIG. 2 is a view in section taken along the line Illl of FIG. I illustrating in detail the plurality of valves in their operative positions and the gears of the timing device.

FIG. 3 is a view in section of a rotary percussion drill head with a cylinder housing the reciprocating piston and having pairs of openings on opposite sides of the piston.

FIG. 4 is a view in section of the pressure accumulators illustrated in FIG. 1 connected to the vent or return conduit.

FIG. 5 is a view in section taken along the line V-V of FIG. 2 illustrating one of the pressure valves in open position.

FIG. 6 is a view in section taken along the line VI-VI illustrating one of the vent valves in a closed position.

FIG. 7 is a view in section taken along the line VII-VII in FIG. 2 illustrating in detail the timing gears that may also fu nction as a positive displacement pump.

FIG. 8 is a view taken along the line VIII-VIII of FIG. 5 illustrating one of the rotary disclike valve members with a peripheral flow recess passage through a portion thereof.

FIG. 9 is a schematic view illustrating the motor-driven valve where the timing device also functions as a positive displacement pump.

FIG. 10 is a schematic view similar to FIG. 9 where the fluid under pressure is supplied from a separate source to the timing portion of the multivalve control device. The timing gears are employed as a motor to open and close the respective valves. The rate of percussion imparted by the piston may be controlled with a flow control valve controlling the rate of flow to the timing gears.

FIG. 11 is a schematic view similar. to FIG. 9 in which separate drive means are provided for the timing device to open and close the respective valves. With this arrangement, the percussion rate can be varied over a wide range.

FIG. 12 is a perspective view of pairs of the disclike valve elements with shafting connecting axially aligned pairs of disclike valve elements.

FIG. 13 is a view partially in section of .a percussion drill head with the cylinder housing and a reciprocating piston having pairs of openings on opposite sides of the piston.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings and particularly to FIG. 3, there is illustrated a drill head generally designated by the numeral 10 that includes a cup-shaped housing 12 with an annular open top portion 14 and a base portion 16. The sidewall of the housing 12 has an opening 18 in which bearings 20 are positioned to support a rotatable shaft 22. A bevel gear 24 is connected to .the shaft 22 within the housing 12. Suitable means, not illustrated, are arranged to rotate the shaft 22 and thus impart rotation to a drill rod 26, as later explained. A top plate 28 encloses the housing opening 14 and is secured to the housing 12 by means of bolts 30. The plate'28 has an upstanding annular collar portion 32 with an annular passageway 34 connected to an outlet opening 36 for removing the dust and cuttings conveyed through the internal passageway 38 of the drill rod 26.

Positioned within the housing 12 is a drill rod support member 40 that has a base portion 42 and a cylindrical sidewall 44. A bevel gear 46 is secured to the outer portion of the cylindrical wall 44 and meshes with the bevel gear 24 to thereby rotate the drill rod support 40within the housing 12. Suitable thrust bearings 48, 50 and 52 are arranged between the housing I2 and the drill rod support member 40 to permit rotation of the drill rod support member relative thereto. The upper portion of the drill rod support member has a socket 54 base portion 42 in which there is positioned a bearing 58. The

support member 40 has an axial passageway 60 therethrough aligned with the opening 56 in which there is positioned a hammer shaft 62. The end portion 64 of the hammer shaft 62 extends through the opening 56 in the support member 40 into the inner portion of housing 12. The hammer shaft 62 has an enlarged other end portion 66 which is positioned in the upper portion of the drill rod support member and is in abutting relation with the base of the drill rod 26 and is operable upon axial reciprocatory movement to impart percussive strokes to the drill rod 26.

' A cylinder generally designated by the numeral 68 has a body portion 70 and end flange members 72 and 74. The end flanges 72 and 74 are secured to the body portion 70 and to the housing base portion 16 by means of bolts 76 and are axially aligned with the hammer shaft 62. The'body portion 70 has an inner cylindrical chamber 78 with an upper annular shoulder portion 80 and a lower annular shoulder portion 82 that provides upper and lower cylindrical chamber portions 84 and 86 of reduced diameter. Positioned within the cylindrical ,chamber portions of reduced diameter are annular bearings piston 92 downwardly in the body portion 70. Similarly, fluid pressure acting on the lower annular surface 100 moves the piston upwardly within the cylinder body portion 78.

The piston 92. has a pair of oppositely extending cylindrical I shafts with intermediate portions 102 and 104. The diameter of; the intermediate portions 102 and 104 is substantially the same as the diameter of the cylindrical chamber portions 84 and 86. There is approximately .002 inch clearance between the surfaces of intermediate portions 102 and 104 and the inner cylindrical wall of chamber portions 84 and 86. With this arrangement, as the cylinder 92 is reciprocated so that the intermediate shaft portions 102 or 104 are moved into the cylindrical chamber portions 84 or 8 6, the fluid entrapped within the chamber portions serves as a liquid cushion for the piston. Because of the slight clearance between the intermediate shaft portions 102 or 104 and the sidewalls of the chamber portions 84 and 86 the fluid is slowly displaced to thereby provide a fluid cushion for the piston 92. There are provided passageways 106 and 108 in the flanges 72 and 74 to receive and return to the tank, the fluid that has leaked past the bearings 88 and 90.

The oppositely extending shafts of piston 92 have end shaft portions 110 and 112 extending therefrom. The end shaft portions are suitably positioned in the annular bearings 88 and 90 to-maintain the piston 92 axially aligned within the cylinder -68. The shaft end portion 1 10 extends through an opening 114 i n'the drillhead housing bottom portion 16 and has an end surface 116 in abutting relation with the end portion 64 of hammer shaft 62. With this arrangement, upward movement imparted to the piston 92 is transmitted through the shaft end portion 110 to the end surface 116 which, in turn, strikes the end portion 64 of hammer shaft 62 and moves the hammer shaft upwardly within the drill rod support member 40. Since the upper portion 66 of hammer shaft 62 is in abutting relation with the base of drill rod 26 this upward percussive force or motion is transmitted to the drill rod 26. Since the drill rod is continually urged against the base of the hole being drilled by the drilling machine, the drill rod 26 and hammer shaft 62 are moved downwardly within the drill rod support 40 when the piston 92 is moved downwardly within the cylinder 68. Thus, each upward movement of the piston 92 imparts an upward percussive blow to the drill hammer 62 which is, in turn, transmitted to the drill rod 26. Positive fluid pressure is employed to move the piston 92 downwardly away from the drill hammer end portion 64.

The cylinder body portion 70 has an upper inlet port 118 opening into the cylindrical passageway 78 within the body portion 70 and an upper outlet port 120. It should be noted in the particular embodiment illustrated, the inlet port 118 and outlet port 120 both communicate with the cylindrical chamber 78. An inlet conduit 122 is connected to inlet port 118 and vent conduit124 is connected to outlet por t l20. Similarly, the cylinder 68 has a lower inlet port 126 below the piston 92 and an outlet port 128.. Conduits 130 and 132 are connected to the respective inlet and outlet ports 126 and 128. With this arrangement, fluid supplied-through inlet conduit 122 will fill the annular chamber between the cylindrical intermediate shaft portion 102 and the cylindrical walls of chamber 78 and displace or move the cylinder 92 downwardly. Since the lower portion of the cylinder is vented through outlet conduit 132, fluid remains in the annular chamber between the shaft 112 and the cylindrical wall of chamber portion 86. The intermediate shaft member 104 has a shoulder or secondary piston face 135 that contacts the fluid within the annular chamber designated by the numeral 134 and, with the clearance between the surface of intermediate shaft portion 104 and wall 86, the fluid slowly flows therebetween and prevents metal-to-metal contact on the upward and downward strokes of the piston.

Referring to FIGS. 1 and 2, there is illustrated a multiport control device generally designated by the numeral 136 that has an upper vent valve 138, an upper pressure valve 140, a lower pressure valve 142, a lower ventvalve 144 and a timing device pump combination 146. The upper vent valve 138 has a port 148 to which conduit 124 is connected. The other end of conduit 124 is connected to vent port 120 of cylinder 68 (FIG. 3). A pressure accumulator generallydesignated by the numeral 150 is connected in series with the conduit 124 and port 148. The upper pressure valve 140 has a port 152. Conduit 122 is connected to port 152 and to port 118 of the cylinder 68 (FIG. 3). i

The lower pressure valve 142 has a port 154 connected to conduit 130. The other end of conduit 130 is connected to the lower pressure port 126 in cylinder 68. The lower vent valve 144 has a port 156 that is connected to conduit 132. The other end of conduit 132 is connected to the lower vent port 128 in cylinder 68. A pressure accumulator 158 is connected in series with the conduit 132 and port 156 of vent valve 144.

The multivalve control device 136 includes an end plate 160 with a plurality of longitudinal bolt passageways 162 therethrough adjacent the circumferential edge portion and a pair of recessed cup-shaped portions 164 and 166. Annular bearings 168 and 170 are positioned in the recessed portions 164 and 166. The upper vent valve 138 includes a pair of disclike valve members 172 and 174 with peripheral grooved portions 176 and 178 extending around about l80 to l90 of the periphery. The member 172 has oppositely extending shaft end portions 180 and 182. The shaft end portion 180 is positioned in the bearing 168 in recess 164. Similarly, the member 174 has oppositely extending shaft end portions 184 and 186. The shaft end portion 184 is rotatably positioned in bearing 170 in recessed portion 176. An annular valve housing 188 having port 148 therein extends around the pair of disclike members 172 and 174 and has a central chamber therein. The housing is similar to that illustrated in FIGS. 5 and 6. The valve housing 188 has longitudinally extending bolt apertures 190 aligned with the bolt apertures 162. The valve housing has one planar end wall 192 in abutting relation with a mating end wall of the end plate 160 to form a seal therebetween. A support housing 194 has a plurality of bolt passageways 196 aligned with bolt passageways 190 and 162 and has a pair of longitudinal passageways 198 and 200 with enlarged end portions 202 and 204 adjacent the opposite end wall 207 of valve housing 188. Bearings 206 and 208 are positioned in enlarged portions 202 and 204 and shaft end portions 182 and 186 of disclike valve members 172 and 174 are rotatably supported in the bearings 206 and 208. The passageways 198 and 200 have enlarged portions 210 and 212 in which bearings 214 and 216 are positioned.

The upper pressure valve 140 has a pair of disclike valve members 218 and 220 which are similarto the disclike valve members 172 and 174 previously described. The disclike valve member 218 has a shaft portion 222 positioned in the recessed portion 210 of support member'l94 and disclike valve member220 has a shaft end portion 224 positioned in the enlarged portion 212. The disclike valve members 218 and 220 have recessed peripheral portions 226 and 228 similar to the recessed portions 176 and 178 that extend around 190 of the periphery of both of the valve members 218 and 220. The shaft end portions 182 and 222 have axial passageways 230 and 232 therein with suitable keyways 234 and 236. A shaft 238 is positioned in the passageway 198 Ofsupport member 194 and extends into the recessed portions 230 and 232 and is suitably keyed to the end shafts 182 and 230 so that valve members 172 and 218 rotate in timed relation to each other.

The disclike valve member 220 is similarly connected to disclike valve member 174 by means of shaft 240 keyed to the shaft end portions 186 and 224. As illustrated in FIG. 2, the upper vent valve 138 is open in that the peripheral recessed portions 176 and 178 are facing-each other and in overlying relation to form a passageway therebetween. The upper pressure valve 140 is closed in that the recessed portions 226 and 228 are spaced from each other. The upper pressure valve 140 has an external housing 242 which is similar in construction to the external housing 188 of the ventvalve 138. The housings 188 and 242 and the disclike valve members housed therein are interchangeable. v 1

Abutting the wall of valve housing 242 is a support member 244 which is similar to the support member 194 and is interchangeable therewith. The support member 244 has passageways 246 and 248 extending therethrou'gh-in which is closed because the recessed portions 292 and 294 are spaced from each other.

FIG. 12 illustrates in detail the manner in which the pairs of disclike valve members 256 and 258 are connected to the adjacent pair of disclike valve members 288 and 290 by means of the shafts 282 and 284. It should be understood that the disclike valve members may have either a longitudinal bore therethrough or recessed portions to receive end portions of the shafts therein. The plurality of shafts connecting the adjacent axially aligned disclike valve members'may be referred to as shafting connecting the respective disclike valve members.

Another support member 304 is positionedin abutting relation with the valve housing 286 and is similar in construction to the previously described support members. The support member 304 has passageways 306 and 308 in which shafts 310 and 312 are positioned. The shaft 310 extends into a recessed portion of shaft end portions 298 and is keyed therein. Similarly, shaft 312 extends into a recess in shaft end portion 302 and is also keyed therein.

The combination timingdevice and positive displacement pump 146 has a housing 314 positioned in abutting relation with the support member 304. The housing has longitudinal bolt passageways 316 and a pair of meshing gears 318 and 320 are positioned in the housing 314. The gear 318 has shaft end portions 322 and 324. Similarly, the gear 320 has shaft end portions 326 and 328. The shaft end portions 322 and 326 are positioned in the enlarged portions of passageways 306-and 308 and shafts 310 and 312 extend into recessed portions of the respective gears 318 and 320 and are keyed thereto so that gears 318 and 320 are connected to the previously described disclike valve members.

An end plate 330 has bolt-receiving apertures 332 and a cup-shaped recessed portion 334 for receiving the shaft end portion 324 of gear 318. The end plate 330 has a passageway 336 with an enlarged portion 338. The shaft end portion 328 shafts 250 and 252 are positioned and extend into recessed portions within the shaft end portions of disclike valve members 218 and 220.

The lower pressure valve 142 is positioned adjacent the support member 244 and has a housing 254. whichis similar to the housings 242 and 188. Within the housing 254 there are positioned a pair of disclike valve members 256 and 258 which have peripheral recessed portions 260 and 262. The disclike portions 264 and 268 extend into enlarged passageways in the support member 244 and have recessed portions 272 and 274 in which the shafts 250 and 252 are positioned and nonrotatably keyed thereto so that the disclike valve members 256 and 258 rotate in timed relation with the other previously described disclike valve members. A support member 276 similar to support members 244 and 194 is positioned in abutting relation with the upper pressure valve housing 254 and has passageways 278 arid 280 therethrough in which shafts 282 and 284 are positioned. The shafts-282 and 284 extend into recessed portions of disclike valve member shaft end portions 266 and 270 and are keyed thereto.

The lower vent valve 144 has a housing 286 in which a pair of disclike valve members 288 and 290 are positioned with recessed peripheral portions 292 and 294. The disclike valve members have shaft end portions 296, 298, 31 1 and 302. All of the shaft end portions have recessed portions therein and shafts 282 and 284 extend into the recessed portion of shaft end portions 296 and 300 and are keyedtherein to rotatably connect the disclike valve members 288 and 290 to the disclike valve members 256 and 258 and the other previously described valve members. It should be noted that the disclike valve members 256 and 258 of the lower vent valve have their recessed portions 260 and 262 abutting each other to form a passageway therebetween so that the lower vent valve as illustrated in H6. 2 is open, whereas the lower pressure valve 144,

of gear 320 is supported in the enlarged portion 338 of passageway 336. A drive shaft 340 has an end portion extending into an axial passageway 342 of gear 320 and is keyed thereto so that rotation of shaft 340 rotates both gears 318 and 320 and by the previously described connections all of the disclike valve members within the multiport control device 136. The end plate 330 has a motor mounting bracket 344 thereon arranged to support a drive motor or the likeconnected to the shaft 340. It should be understood, however, the use of the shaft 340 as a driving means is optional, as later described.

The previously described valve members are positioned in stacked relation as illustrated in FIGS. 1 and 2 and are secured in this position by the elongated bolts 346 extending through the bolt apertures previously described. Referring to FIG. 1, the support member 194 has an outlet port 348 therein and an internal passageway 350 that is connected to an internal passageway 352 in the upper vent valve housing 188. The support member 244 has a port 354 that opens into passageway 356. The passageway 356 is connected. to passageways 358 and 360 in valve housing 242 and 254 of the upper and lower pressure valves and 142 respectively. The support member 276 has a port 362 opening into passageway 364 which is connected to a passageway 366 in the housing 280 of lower vent valve 144. The support member 304 has a pair of ports 368 and 370 that open into respective passageways 372 and 374. The housing 314 has passageways 376 and 378 that are connected to the passageways 372 and 374 respectively.

As previously stated, the valves 138, 140, 142 and 144 are of similar construction and some of the elements thereof are interchangeable. Similarly, the support members 194 and 276 are of similar construction and are interchangeble. The support member 244 differs from support members 194 and 276 in that the passageway 356 opens into both valves 140 and 142. The support member 304 also has a pair of ports 368 and 370 and passageways 372 and 374.

FIG. 5 is a sectional view in elevation of the lower pressure valve 142 and illustrates the housing 254 with the peripheral bolt passageways for bolts 346 and the disclike valve members 256 and 258 with the peripheral recessed portions 260 and 262. In FIG. 5, the recessed portions 260 and 262 are illustrated as extending around 180 of the disclike valve member "periphery. In FIG. 6, however, the recessed portions 292 and 294 are, for illustrative purposes, illustrated as extending around about 190 of the disclike valve member periphery. It I'is preferred to' have the same peripheral recessed portion for i' all the disclike valve members so that the plurality of valves iwill open and close in timed relation. Where the recessed portions extend around 180 of the periphery, the volume of tiliquid displaced by the timing gears 318 and 320 in one-half a "revolution should be about 10 percent greater than the volume of liquid required to displace the piston in the cylinder for a complete stroke of the piston. The excess fluid enters an shown but may be similar to the accumulators 150 or 158.

jWith this arrangement, an accumulator must be provided in the conduit between ports 370 and 354 because all of the valves in the control device are closed and the excess volume of fluid supplied by the timing device pump combination 146 must be displaced in the accumulator.

Where the recessed portions extend around 190, the accu- -.mu lator in the conduit connecting ports 370 and 354 is not necessary because there is an overlap where both pressure valves 140 and 142 are open for about 10 of the revolution. ,The metering gears should, however, be made larger to compensate for the loss of fluid while all valves are open during the i 10 overlap. The dimension of the timing gears and the piston .and cylinder may be varied to control the amount of fluid entering the accumulator 150 and the resilience of the spring :394 may be varied to control the force exerted by the piston in :lthe cylinder.

- In FIG. 5, the ports 154 and passageway 360 communicate through the mating recessed portions 260 and 2620f the disclike valve members 256 and 258 when positioned as illustrated in FIG. 5 so that liquid supplied to passageway 360 'flows through the openings formed by the mating recessed portions 260 and 262 to the port 154. The disclike valve "member 256 is illustrated in FIG. 8 with the recessed portion 260 and the shaft end portions 264 and 266. The shaft 250 is illustrated as extending into a recessed portion of shaft end j'portion 264 and is keyed therein. Similarly, the shaft 282 extends into a recessed portion of shaft end portions 266 and is keyed thereto.

FIG. 6 is a sectional view in elevation of the lower vent valve 144 and illustrates the disclike valve members 288 and 290 within the housing 286. The recessed portions 292 and 294 are spaced from each other and the passageway 366 does not communicate with the port 156 because the peripheral portions of the disclike valve members 288 and 290 are abutting each other and close the opening between the passageway 366 and port 156.

'FIG. 7 is a sectional view in elevation of the metering pump device 146. The housing 314 has passageways 376 and 378 that open into a chamber 380 in which the gears 318 and 320 are positioned in meshing relation to each other. The gears 318 and 320 are arranged upon rotation to displace fluid between the meshing gear teeth and thereby positively displace fluid for flow from one passageway to the other through chamber 380. The valve housing, as for example, valve hous- -ing 254 and 286, also include a chamber 382 that communicates with the opposed passageways. The disclike valve inembers, as for example, valve members 256 and 258 in valve 142, are positioned in the chamber 382 and upon rotation permit the flow of fluid through the chamber from one port to the other or when in the position as illustrated in FIG. 6, close the chamber 382 and prevent the flow of fluid therethrough from one passageway to the other.

It should be noted as illustrated in FIG. 2, that the disclike valve members are so connected to the adjacent disclike valve members that when the upper vent valve is opened. as illustrated in FIG. 2, the upper pressure valve MI) is closed and the lower pressure valve 142 is open and the lower vent valve I44 is closed. With this arrangement, as illustrated in FIG. 2, fluid under pressure is being supplied through lower pressure valve 142, conduit 130, to the face of piston 92 (FIG. 3) to move the piston 92 upwardly. When the lower vent valve 144 is closed the upper vent valve 138 is opened to permit the fluid within the cylinder above the piston 92 to be displaced through conduit 124. The upper pressure valve 242 is closed so that fluid under pressure is not being supplied to the upper portion of the cylinder 68. Where the peripheral recessed portions extend around more than 180 of the disclike valve member periphery, there is a slight overlap where, for a short period of time, both the vent and pressure valves are open.

A suitable pressure accumulator such as accumulator 150 or 158 is positioned in series with the conduits 124 and 132 and ports I48 and 156 of the vent valves 138 and 144 to displace fluid supplied to the cylinder in excess of the volume of the annular space between the piston and the cylinder. One of the pressure accumulators .is illustrated in detail in FIG. 4 and includes a cylindrical housing 384 with a base portion 386 that has a longitudinal passageway 388 that is connected in series with the conduit 24 and the port 148. The housing 384 has an opening 390 into the passageway 388. Within the cylindrical housing 384 there is positioned a piston 392' and a coil spring 394 that urges the piston toward the base 386. An adjusting device 396 is provided to increase or decrease the tension on spring 294. An exhaust port 398 is provided above the piston 392 to vent the slight amount of fluid that leaks past the piston 392 within the housing 384. The piston 392 is displaced upwardly by the excess fluid supplied to the cylinder 68 (FIG. 3). When the vent valve is opened the piston 392 displaces the fluid within the housing 384 into the conduit 124.

In FIG. 13 there is illustrated a percussion drill that includes a piston cylinder assembly similarto that illustrated in FIG. 3. Similar numerals in FIG. 13 will designate similar parts of the piston cylinder assembly.

The percussion drill in FIG. 13 is generally designated by the numeral 550 and includes a chuck housing 552, a piston cylinder assembly 554 and a drill indexing housing generally designated by the numeral 556. The chuck housing 552 and drill indexing housing 556 are secured to the cylinder 68 by the bolts 76 and are axially aligned. The chuck housing 552 includes a chuck 558 with a central bore 560 in which the base 562 of drill rod 564is positioned. The drill rod 564 is movable vertically in the chuck 558 and is rotatable by means of the indexing housing 556, later described. The piston cylinder assembly 554 has the piston end portion in abutting relation with the end portion of drill rod 564. A, sleeve member 566 nonrotatably secures the drill rod 564 to the piston end portion 110 so that rotation of piston 92 by means of indexing mechanism 56 is transmitted to the drill rod 564.

The cylinder 68 has a pressure inlet port 118 and a pressure outlet port 120 above the piston 92 and pressure inlet port 126 and pressure outlet port 128 below the piston 92 as previously described in reference to FIG. 3. With this arrangement fluid supplied through conduit 122 to the cylinder 68 moves the piston 92 downwardly and moves the end of the drill rod 564 away from the base of the hole being drilled. Fluid supplied through conduit 130 moves the piston 92 upwardly to transmit through the shaft 110 upward percussive movement to the drill rod 566. Thus, reciprocation of piston 92 within cylinder 68 provides the percussive blows to the base of the drill rod 564 to thereby dislodge material in the hole being drilled.

The end shaft section 112 has splined portions 568 which nonrotatably connect the piston 92 to an indexing mechanism generally designated by the numeral 570 that is housed within the drill indexing housing 556. The drill indexing mechanism 570 may be conventional and similar to the indexing mechanisms illustrated in U.S. Pat. No. 3,059,618 and U.S. Pat. No. 3,044,448. The indexing mechanism 570 is so arranged that on the return downward stroke of the piston 92 the piston rotates through a fraction of a revolution to thereby rotate and index the drill bit for the next percussive stroke. The rotation of the piston 92 is transmitted through the sleeve 566 to the drill rod 564. Thus, with'the above-discussed arrangement, it is now possible to provide percussive forces to a reciprocating percussion drill with a fluid supplied to the piston cylinder assembly 554 from the multiport control device 136 illustrated in FIGS. 1 and 2.

The high-speed rotary percussion drill illustrated in FIG. 3 operates as follows. The drill rod support member 40 and the drill rod 26 nonrotatably connected thereto is rotated at high rotary speed by means of drive shaft 22 transmitting rotation through bevel gears 24 and 46. The hammer shaft 62 and the piston 92 rotate at substantially the same speed as the drill rod support member 40. The percussive forces are imparted to the drill rod 26 by supplying fluid under pressure alternately through conduits 122 and 130 from the multiport control device 136.

It will be appreciated that the previously described multiport control device 136 can be utilized to provide reciprocatory motion for the piston 92 within cylinder 68. FIGS. 9, l and 11 schematically illustrate various arrangements for supplying the fluid under pressure to the opposite faces of the piston 92 within the cylinder 68. Although not illustrated in FIGS. 9, and 11, it should be understood that accumulators 150 and 158 are positioned in the conduits 124 and 132 as illustrated in FIG. 1. In FIG. 9, a motor 500 is connected to shaft 340 and is arranged to rotate the gears 318 and 320 within the combined pump and timing device 146. In the embodiment illustrated in FIG. 9, the timing device pump combination 146 serves both as a timing device and as a positive displacement pump. The port 370 is connected to a source of fluid by a conduit 502. The fluid displaced by the gears 318 and 320 flows through conduit 504 into passageways 360 and 358 of the upper and lower pressure valves 142 and 140 respectively. Where the recessed portions of the valves extend around 180 of the periphery, a pressure accumulator is positioned in conduit 504. The upper pressure valve 140 is connected by means of conduit 122 to the cylinder 68 and the lower pressure valve 142 is connected by conduit 130 to the cylinder 68 as previously described. The upper vent valve 138 is in turn connected by conduit 124 to the cylinder 68 and the lower vent valve 144 is connected by conduit 132 to the lower portion of cylinder 68. The vent valves 138 and 144 are connected by means of conduits 506 and 508 to a reservoir or tank 510. With this arrangement, the metering gears may be so sized that they will displace the same amount of fluid in one-half of a revolution as is displaced in one end of the cylinder. Where the metering gears have a greater displacement, a pressure accumulator must be positioned in conduit 504 to take up and displace the excess fluid supplied by the metering gears in one-half a revolution.

In FIG. 10, a separate pump 512 is provided, driven by the motor 500. The fluid under pressure from pump 512 is supplied through conduit 514 to the timing device 146. The fluid under pressure rotates the gears and opens and closes the valves as previously discussed and supplies the fluid under pressure through conduit 514 to the pressure valves 140 and 142. Wlth this arrangement, the metering gears should have the same displacement in one-half revolution as the displacement in one end of the cylinder. Where the metering gears displace greater volumes of fluid, an accumulator should be positioned in conduit 504.

FIG. 11 illustrates an arrangement where fluid under pres sure is delivered from the pump 512 directly to the pressure valves 140 and 142. A separate variable speed motor 516 is connected to a speed reducer 518 and the shaft 340 of the timing gears 318 and 320. A separate source of lubricant is supplied to the timing gears in this embodiment. With this arrangement, the motor 516 controls the opening and closingof the pressure and vent valves and also controls the number of percussive strokes per unit of time so that one can vary the speed of motor 516 and thereby vary the percussive strokes over a relatively wide range.

According to the provisions of the patent statutes, I have explained the principle, preferred construction and mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiments.

Iclaim:

1. A hydraulically actuated rotary percussion drill comprising:

a drill head housing;

a rotary drill rod support positioned in said housing and having a central passageway therethrough opening into a drill rod receiver at one end and into said housing at the other end;

a drill rod having an end portion nonrotatably secured in said receiver and extending longitudinally therefrom;

means to rotate said drill rod support in said housing and thereby impart rotary motion to said drill rod;

a hammer shaft positioned in said drill rod support central passageway and having one end portion extend into said receiver and the other end portion extend into said houssaid housing having a cylinder portion with a cylindrical chamber axially aligned with said drill rod support central passageway;

a piston positioned in said cylinder portion and having a rod end portion abutting said hammer shaft end portion;

said cylinder portion having openings on opposite sides of said piston;

a control valve assembly having an upper pressure valve, an upper vent valve, a lower pressure valve and a lower vent valve, said upper pressure valve and said upper vent valve connected to said cylinder above said piston, said lower pressure valve and said lower vent valve connected to said cylinder below said piston;

means to supply liquid under pressure lower pressure valves; and

means connecting said valves so that said upper pressure valve and said lower pressure valve alternately open and close to alternately supply fluid under pressure to the upper and lower portions of said cylinder and reciprocate said piston therein to thereby impart percussive blows to said drill rod through said hammer shaft by said piston rod end portion.

2. A hydraulically actuated rotary percussion drill as set forth in claim 1 in which, said means connecting said valves in cludes timing means to control the rate of opening and closing of said valve members to thereby control the number of percussive blows imparted to the drill rodper unit time.

3. A hydraulically actuated rotary percussion drill as set forth in claim 1 in which, said means connecting said valve includes metering means to control the volume of liquid supplied through said pressure valves to said cylinder.

4. A hydraulically actuated rotary percussion drill as set forth in claim 1 in which, said means connecting said valves includes a timing means and a metering means, said timing means operable to control the time that the respective valves remain open and said metering means controls the volume of liquid supplied through said pressure valves to said cylinder while said pressure valves are open.

5. A hydraulically actuated rotary' percussion drill as set forth in claim 1 in which, said means connecting said valves includes positive displacement pump means operable upon actuation to supply liquid to said pressure valve.

6. A hydraulically actuated rotary percussion drill as set forth in claim 1 in which, said cylinder portion includes:

a chamber, a first pressure opening into said chamber above said piston and a first vent opening into said chamber above said piston, 21 second pressure opening into said chamber below said piston and a second vent opening into said chamber below said piston;

conduit means connecting said upper pressure valve to said first pressure opening, said upper vent valve to said first vent opening, said lower pressure valve to said second pressure opening and said lower vent valve to said lower vent opening; and

to said upper and r fill liquid displacement means in said conduit means between said upper vent valve and said first vent opening and in said conduit means between said lower vent valve and said second opening.

7. A hydraulically actuated rotary percussion drill as set forth in claim 6 in which said liquid displacement means includes a pressure accumulator operable to receive fluid supplied to said cylinder in excess of the fluid required to displace said piston, said pressure accumulator having resilient means to exert a pressure on the fluid contained therein.

8. A hydraulically actuated reciprocating drill comprising:

a drill head housing having a drill support portion, a

cylinder portion having a cylindrical chamber, and a drill a piston positioned in said cylinder portion and having a rod end portion abutting said drill rod end portion; said cylinder portion having openings into said chamber on opposite sides of said piston;

a control valve assembly having an upper pressure valve, an upper vent valve, a lower pressure valve and a lower vent valve, said upper pressure valve and said upper vent valve connected to said cylinder portion above said piston, said lower pressure valve and said lower vent valve connected to said cylinder portion below said piston;

means to supply liquid under pressure to said upper and lower pressure valves;

means connecting said valve members so that said upper pressure valve and said lower pressure valve alternately open and close to alternately supply liquid under pressure to the upper and lower portions of said cylinder and reciprocate said piston therein to thereby impart percussive blows to said drill rod end portion by said piston rod end portion; and

means in said indexing portion of said drill head housing to rotate said piston and said drill rod a portion ofa revolution with each stroke of said piston. 

